Since each feedyard has its own peculiar location and operation situation, it is usually different than the feedyard “down the road.” Consequently, it is difficult to give any “pat” recommendations on wind- break locations. Some research, however, and considerable observation and experience at feedyard sites have shown certain location items about windbreaks that can be applied to different situations. Wind sweeping around the corners of buildings, silos, or ends of windbreaks or other barriers can cause drafts a considerable distance away. The velocity of wind increases 10 to 20 percent and even higher when it goes around the end of a shelterbelt. Remember that a windbreak fencing does not stop the wind. It simply deflects it. Consequently, the windbreak directs the wind off to someplace else. When locating windbreak fencings, arrange and locate them so the winter wind will “flow” away or otherwise not adversely affect cattle eating, watering, or resting areas.
Research and experiences have shown that the most effective windbreak for wind protection is 75% to 80% solid (20% to 25% open or porous). Consequently, the “slatted” type of windbreak fencing is preferred and recommended. This slatted type allows some air to flow or “leak” through. This air flow can be felt a few feet away on the leeward side of the fence. This same air flow, however, prevents much of the downdrafting and swirling that occurs by a solid board fence. The effective distance protected downwind by the fence is increased by relieving the downdraft and swirling. This action is comparable to that used with “windproof” cigarette lighters. Natural tree shelterbelts are usually 30% to 50% solid during winter when there are no leaves on the trees. This is considerably more open than desirable. Shelterbelts that have a row of evergreens are better wind barriers. In general, wind velocities are reduced 5 to 10 barrier heights away on the windward side and 10 to 30 heights away on the leeward side of a windbreak. The wind velocity reduction beyond 20 heights on the leeward is minor, however. A 12-foot high, slatted board fence, for example, can be expected to give fair wind protection downwind to about 200 feet away. The wind velocity reduction on the upwind or windward side accounts for the snow drift on the windward side of snow fences, shelterbelts, buildings, and other barriers.
Again, when the wind velocity is reduced snow drifts will build up. It is recommended to locate buildings, cattle yard areas, feed storage, etc. about 185 feet beyond and downwind from the outside or windward row of trees in a shelterbelt (not the inside or leeward row of trees). Major snow drifting will generally occur within this 185-foot zone. It is difficult to eliminate snow drifting within the feedlot area itself as wind control there is more important than snow control. Utilizing the porous or slatted type board fences, however, allows the snow to be spread over a larger area rather than pile up next to a fence. Snow drifting near the windbreak fencingis more common with a solid . The solid fence allows very little wind to come through it and relieve the downdraft and swirling on the leeward side as does the slatted fence. Wind coming over the top of a building is another troublesome item. In an actual situation the wind comes over the ridge, drops down, swirls around and often leaves a big snowdrift in front of or inside an open front shed! The idea of a slatted wind barrier installed along the ridge has been tried. It has given limited success, however. Again, so much depends on wind barrier upwind and adjacent to the building. Offset a windbreak fence to the side and to the rear of an open-front resting shed. This provides a “swirl” chamber to the side and reduces wind in front of the shed. A 16-foot offset to the side and rear of the front corners is minimum. A larger distance can be used. However, keep in mind wind sweep over the top of the windbreak. The offset fence seems to be particularly useful in controlling winds that approach the building at an angle.
Drafts and funnelling between sheds, around silos, and other critical areas can be reduced by installing a slatted wind barrier. A slatted or porous barrier is especially recommended over a solid type for these locations. This avoids development of added downdrafts or swirling. Partition windbreak fencings may be required inside wide, long buildings, particularly those with open fronts. This is to reduce drafts that can develop around a large, confined air space. Wind currents deflected from adjacent buildings, silos, feeders, stacks, etc. and that come around the end or over the top of the shed are often the cause of these drafts. Closing the endwalls of the shed and using large doorways that can be opened or closed is often necessary. Windbreak fences are usually installed in the partition fences between feedyard pens. This permits using the fence for dividing the pens as well as for wind protection and also for shade. Sliding or swinging “doors” or gates are desirable to prevent wind from funneling down through fenceline feed alleys. These can be left open for hot weather air movement. These moveable windbreaks can aid cattle comfort while at the bunkmand reduce waste from blowing feed. Windbreak fences are also installed in the fence- lines around the outside of the feedyard. These protect the cattle from general prevailing winter winds. Haystacks, chaff piles, trees, and buildings can also be utilized for this purpose. Recently some operators have installed slatted windbreak fences at the top of earth resting mounds in the central part of the cattle yard area. This permits the cattle to utilize either side of the windbreak fencing. It also locates wind protection nearer the feedbunk and waterer areas. These fences are usually installed at an angle northeast to southwest so to provide the best wind protection against prevailing winds, promote sunlight to dry on either side, and provide drainage out of the feedyard.
Snow fencing can be used to provide temporary wind and snow control. This could be in a short-term, winter feeding area, for example. Snow fencing several “tiers” high has been constructed and used. The height results in effectiveness being extended over a long distance away. Snow fence is too porous to provide a real good windbreak. Also, it is not heavily constructed so it will not take long abuse by livestock. Consequently, its limited use is advised.